Upon shooting a picture with strobe, automatic light control is normally executed by making a pre-light emission, measuring the objects reflected light, and determining the amount of main light needed on the basis of the photometry result.
Normally, a series of these processes are done depending on the operation state of a release switch (SW). More specifically, main light emission is performed after pre-light emission, photometry, and determination of the main light emitting amount are made while the release SW is pressed at the full stroke position.
Also, an automatic light control camera is known (e.g., Japanese Patent Laid-Open Nos. 61-156239, 61-156240, and 60-61733). That is, a member independent from the release SW makes pre-light emission and photometry of object reflected light by the pre-light emission, so as to determine a light emitting amount of a strobe in advance, and main light emission is then made by the release SW. According to these patent references 1 to 3, since the light emitting amount of the strobe can be determined in advance, even when a light control area is located at the center of the visual field and an object is not located at the center, pre-light emission is made while locating the object at the center upon pre-light emission. After that, even when shooting is made by changing the composition (shooting direction, field angle), an appropriate exposure value can be obtained upon shooting.
However, when automatic exposure shooting is performed by controlling object reflected light of the strobe, and a sub object with a high reflectance such as glass, a mirror, or the like is present near a main object, the exposure value is determined under the influence of the sub object with the high reflectance and, consequently, the main object is underexposed.
As a measure to be taken against this problem, an automatic light control camera which makes a strobe perform pre-light emission immediately before shooting under the assumption that a main object is located at an in-focus distance is known (e.g., Japanese Patent Laid-Open No. 3-287240). This technique uses a photometry sensor which divides a shooting area into a plurality of areas, and can make photometry on respective areas. Reflected light returning from an object is measured, and when the photometry result of a given area is higher than the brightness calculated from a shooting distance, it is determined that a high-reflecting object is present in that area, and the area is excluded from the light control areas, thus minimizing the influence of abnormal reflection.
In the automatic light control cameras disclosed in patent references 1 to 3, the strobe light control amount can be determined in advance. However, since pre-light emission is made to determine the main light emitting amount of the strobe irrespective of the in-focus state of the camera, the exposure value often becomes inaccurate. That is, since the open f-number of a lens changes depending on the extension position of the lens, when the extension amount becomes large in e.g., macro shooting, the exposure value is often changed by about one level due to variations of the open f-number upon extension. When an abnormal reflecting object such as glass or the like is present upon pre-light emission, underexposure occurs due to that influence. In patent reference 4, the influence of underexposure when an abnormal reflecting object such as glass or the like is present can be minimized, but it is difficult to obtain an appropriate exposure value when an object falls outside the light control range.